1. Technical Field
The embodiments described herein relate to a memory module, and more particularly, to a memory module including a plurality of ranks.
2. Related Art
In general, semiconductor memories are manufactured in the forms of modules. A module is a functional unit having an independent function in a system. A conventional memory module may include one or more ranks according to the structure of a memory system. The rank includes a plurality of semiconductor element packages that are controlled in the same condition by one chip selection signal ‘CS’ or one chip enable signal ‘CE’.
Specifically, each rank having a plurality of semiconductor element packages are mounted to a printed circuit board (PCB), and the PCB is connected to, for example, a panel by a plurality of connection terminals. In a conventional semiconductor memory, the chip selection signal ‘CS’ or the chip enable signal ‘CE’ is used to identify the rank.
However, as the number of ranks mounted to the memory module increases, the number of pins of the memory module for supplying the chip selection signals ‘CS’ or the chip enable signals ‘CE’ required to select the ranks also increases. It is difficult to add pins to each rank since the number of pins provided in the memory module is limited.